By Jim Donovan

PHILADELPHIA (CBS) — Are you thinking about getting your carpets cleaned and tempted by ads offering rock bottom prices? But how many of those ads are too good to be true? In this week’s Angie’s List report, Jim Donovan explains what you should know so that carpet cleaning doesn’t end up ruining your budget.

Wendie Zeller’s dog, Jack, isn’t exactly easy on her carpets. So when she saw an online deal for professional carpet cleaning, she jumped at the offer.

“Good price, I needed the bedrooms done, and for four rooms, so I just bought it,” said Zeller.

It was exactly the deal Wendie needed. That is until the cleaner showed up at her door.

“It was awful. You know, he had told me that because my carpets were so dirty that they would need to do a deep cleaning, and that would be extra,” said Zeller.

And Wendie’s experience isn’t unique.

“One common complaint we’ve heard over the years when it comes to carpet cleaning companies is suggesting a price that just seems too low to be true. What happens is they get there, and the consumer ends up paying more than they expected,” said Angie’s List founder, Angie Hicks.

In order to avoid added extras, homeowners should insist on a written, detailed estimate of what the company will do for the advertised price. And never be shy about sharing your own family’s details.

“Do you have pets? Do you have kids? Do you have special areas that need treatments because you’ve had spills? The more information you give them, the more prepared they can come to do the actual project in case you need special cleaners for some difficult spots,” said Hicks.

More from Angie:

A professional cleaning will help rid your home of hidden dust and allergens that regular vacuuming can miss, and it will help preserve carpet fibers and keep colors brighter. But getting this work done sometimes comes at too high a price because of disreputable companies who dangle get-in-the-door prices that don’t generally hold up once you let the company inside your home.

The two most common tactics:

• Bait and Switch – This is the offer to get your carpets cleaned for $5 to $10 a room. Usually, the homeowner is told their carpet is in really bad shape and the offer didn’t include pre-spray, deep cleaning, and sometimes even using hot water – all essential to a proper carpet cleaning.

• High-pressure sales – This tactic preys on the homeowner’s desire to get the job done right. Homeowners are told there are some spots that need additional cleaning because of how dirty they are, and that without the extra attention, those areas of the floor will stand out and make the floor look bad.

Angie’s List tips to avoid getting scammed:

• Insist on a written estimate that details all charges – and read the fine print.

• Don’t guess if you don’t understand anything on the estimate. Do they charge by the hour or for the square feet of the room? Are they going to charge you for the square feet where your master bed is that you just want to be cleaned around? Do you need to move your furniture, or will they charge you to do that? Are all pre-sprays and other tasks included or add-ons?

• Your carpet cleaner should be certified by the IICRC (Institution of Inspection Cleaning and Restoration Certification.) You can check at www.iicrc.org.

• Is there a guarantee? A good company will return to clean spots that reappear within a short period of time.

• Watch out for those companies who come in and out in a hurry. It takes time to go through the process from start to finish.

• Does the company use hot water from its truck? Or will they be using your water?

• Do they have liability and insurance? If they break something in your home, will they pay to fix it or leave you with the cost?

• Ask how much experience they have with cleaning carpets.

• Make sure they use the right type of solution on your carpet.

Types of Cleaning Methods:

• “Steam cleaning” is probably the most well-known type of carpet cleaning. To the pros, it’s better known as hot water extraction cleaning, because it involves a pre-treatment and then a blast of water (up to 250 degrees!) going on and off of the carpet simultaneously. This is usually the only type of cleaning covered by a carpet warranty.

• Carbonated cleaning allows cleaning agents to get to the carpet fibers with very little wetting. The solution doesn’t contain the oil or detergents that typically leave a dirt-attracting residue, and dissolved dirt is removed with a machine that rubs cotton pads over the carpet.

• The HOST system is the only all-dry, an all-natural cleaning system that is currently Green Seal certified. It uses an absorbent to pre-treat and cleans the carpet by trapping grease and dirt, which then extracting it. It leaves the carpet ready for immediate use, with no downtime. It’s completely non-toxic, with no threat of moisture or harsh chemicals.

• “Bonnet” cleaning uses spray foam that is removed by a rolling/buffing machine that has a bonnet-like attachment. This is mainly for commercial carpets and is similar to what buffing a hard floor surface is like.

We spoke with some highly-rated carpet cleaners on Angie’s List about keeping your carpet looking great:

• The number one way to keep your carpet looking fresh between professional cleanings is to vacuum regularly – about three times a week. This keeps dirt from settling in.

• Don’t walk around with bare feet – you’ll transfer body oils and contribute a considerable amount of grime to the carpet fibers.

• Don’t leave your furniture in the same place forever; change traffic patterns if you can. Leaving furniture in one position for the life of the carpeting creates worn, dirty paths throughout the home and leaves pristine carpets in areas you never see. Carpet that wears evenly will last and stay cleaner longer.